930 B | 930 chars
import sys
from math import sqrt, pi, sin, factorial, ceil, floor
from datetime import datetime, timedelta
BLANK = " "
# inp = input
inp = lambda : sys.stdin.readline()[:-1].strip()
mii = lambda x = BLANK : [*map(int,inp().split(x))]
mfi = lambda x = BLANK : [*map(float,inp().split(x))]
ii = lambda : int(inp())
fi = lambda : float(inp())
p = print
def f(num, l):
for oper, k in l:
k = int(k)
if oper == "ADD":
num += k
elif oper == "SUBTRACT":
num -= k
if num < 0:
return 1
elif oper == "MULTIPLY":
num *= k
else:
if num % k > 0:
return 1
num //= k
return 0
def solve():
n, k = mii()
s = input()
cnt = 0
for i in range(n // 2):
if s[i] != s[n - i - 1]:
cnt += 1
return abs(k - cnt)
if __name__ == "__main__":
tc = ii()
for t in range(1, tc+1):
ret = solve()
p(f"Case #{t}: {ret}")